Man Made Island With Solar Energy Collection Facilities

ABSTRACT

A manmade island [ 10] , adaptable for land-based or sea-based operation holds solar energy collection facilities and is rotatable to optimize the angular orientation thereof relative to the position of the sun. More particularly, the man-made island [ 10]  uses a platform [ 12]  that includes a large outer ring [ 14 ] that floats on a fluid, and a flexible cover [ 16]  attached to the ring [ 14]  to define an airtight volume [ 30 ] below the cover [ 16 ]. A plurality of rows [ 19 ] of solar radiation collector modules are located above the cover [ 16 ], and carry steam generating heat pipes [ 21] . The rows [ 19]  of modules are supported laterally above the cover [ 16 ] by an upper support structure, either a space frame [ 27] , a plurality of cables [ 46]  or a honeycomb [ 75 ]. A compressor [ 32 ] creates an over-pressure within the enclosed volume [ 30]  to vertically support the cover [ 16 ] and the other components mounted thereabove. This structure for supporting the rows [ 19]  of the solar radiation collector modules enables the man-made island [ 10 ] to be constructed with a very large surface area, eventually up to several kilometers in diameter, to better utilize the full potential of the solar concentrators [ 22] , thereby to produce electricity at an economically viable cost. The man-made island [ 10]  includes a number of other structural features that enhance the practical application of solar radiation collection technology.

FIELD OF THE INVENTION

The present invention relates to a man-made island, either land-based orsea-based, that is equipped with solar energy collection facilities.More particularly, the present invention relates to a large scalestructure of this type which is capable of producing electrical energyin a cost-effective manner via solar thermal technology.

BACKGROUND OF THE INVENTION

It is generally accepted that the earth is fast approaching an energycrisis of incalculable proportions. Some say that crisis will occuraround the year 2040.

It appears that solar power may be the only source that cantheoretically overcome the upcoming energy crisis without disruptingenergy costs. Geothermal or tidal energy is a distant secondpossibility, but clearly at much higher costs.

Solar energy is principally suited to mitigating such a future energycrisis. For instance, almost 10'000 GTEP (TEP=Tons Equivalent Petrol) ofsolar radiation reaches the earth every year. Yet, only up to 5 GTEP ofusable solar power would be needed to make a significant step towardenergy sustainability for the earth.

However, there have been practical limitations to large-scaleimplementation of energy producing systems that rely on the sun. Forexample, photovoltaic cells are capable of converting solar energy i.e.sunlight) to usable energy, i.e. electricity. But the overall efficiencyof these devices is about 10-18%, depending on the materials used. Also,higher efficiency generally requires more expensive materials. Stillfurther, the manufacture of photovoltaic cells requires the use ofhighly toxic chemicals, which present a significant and ever-expandingenvironmental problem. Photovoltaic technology will be very importantbut is not yet usable in large scale.

For these reasons, solar thermal technology, the other main technologyfor converting solar energy to electricity, seems to be the bestsolution for producing a sufficient number of GTEPs in the foreseeablefuture, while remaining relatively inexpensive.

A specific solar thermal technology that is now widely being used inpilot applications is the solar parabolic trough. A parabolic trough,shaped like the bottom half of a large drainpipe, reflects sunlight to acentral receiver tube that runs above it. Pressurized water or otherfluids are heated in the tube and used to generate steam, which can thendrive turbo-generators to produce electricity or to provide heat energyfor industry.

In theory, parabolic troughs have had the potential for efficientelectricity production, because they can achieve relatively high turbineinlet temperatures. However, in practice the land requirements for thistechnology are significant. Moreover, recent studies indicate thatpreviously estimated electricity costs, using this technology, may havebeen over-optimistic. In short, the perceived promise on this technologyhas not yet delivered tangible benefits, in a practical sense, eitherdue to inefficiencies or excessive costs, and also due to the inherentlimitations. More specifically, these trough collectors requireexpensive and maintenance-intensive guidance systems to dynamicallyadjust the angular positions of the panels of the trough, dependent onthe sun's position. This requires expensive gear drives, and also largesupport structures that can withstand significant load fluctuations andother structural considerations. They are difficult to clean andsusceptible to wind.

SUMMARY AND OVERVIEW OF THE PREFERRED EMBODIMENTS

It is an object of the present invention to achieve practical andtangible progress in harnessing solar energy, to mitigate the knownconcerns associated with current sources of electrical energy, includingthe possibility of a significant energy crisis in the foreseeablefuture.

It is another object of this invention to facilitate the large scalegeneration of electrical energy via the use of solar radiation, and todo so at an economically viable cost.

The present invention achieves these objectives by placing solarradiation collector modules on a large scale lightweight man-made islandor islands that are low-cost, up to several hundred meters in diameter,and possibly even constructed with a diameter of over one kilometer. Theisland could either operate at sea, on large natural lakes, or on fluidwhere it would be based within a recessed trough of concrete that wouldhold a fluid of appropriate viscosity such as natural oil, or evenwater. The island floats. The word lightweight refers to specificweight, that is platform surface space/overall weight.

This island will be relatively tall in height, e.g., more than 10meters, and possibly even as tall as 30 meters to avoid or at leastminimize any negative effects of rough seas, etc. The land version,however, can theoretically be built much lower, i.e. about 2 meters.Nonetheless, the land-based version could also benefit from a certainheight if it is deployed in a difficult environment, such as a desert.In that case, a minimum height would help in enabling the solarconcentrator modules to be located well above the desert surface, out ofharm's way in the case of sand storms. The greatest abrasive effect ofsand storms occurs in the boundary layer just above the ground.Generally, if the island is taller than the typical height of thisboundary layer, the solar concentrators and other installations will bemuch less prone to suffer defects as a consequence of sand storms. Theisland rotates to track the position of the sun. The land-based versionof this island floats on liquid held within a large ring-shaped trough,via a large outer ring structure sized to fit within the trough. Thesea-based version also uses the outer ring structure. The floating outerring facilitates rotation of the island to a desired orientation, tooptimize the position of the solar radiation collectors located on theisland. Instead of adjusting the positions of the multiple modules ofthe solar collectors, the collector modules are fixed in place, andadjustment of the collector modules is achieved through rotation of theentire island.

The island is essentially circular, although the outer ring structuredoes not have to be exactly circular. For the land version of the islandthe base of the outer ring structure must have a bottom element that isclose to circular in shape, to allow the bottom element to rotate aroundwithin the concrete trough described above. The outer ring could also beassembled from segments of straight pipe sections that have across-section that is round, square, oval or any other suitable shape.The outer ring structure may use typical features that are common inship design, such as isolating the interior volumes within those pipesections, to protect against the possibility of sinking, if the outerring develops a leak. One preferred embodiment of the inventioncontemplates the use of pipe sections that are typically used for oilpipelines.

The outer ring structure could hold or support electrical facilitiessuch as all the equipment for actually producing electrical energy in aRankine cycle, by using the steam delivered from the solar concentratormodules. This would generally be state-of-the-art machinery such assteam turbines or Stirling engines or any other type of machine suitableto use steam to drive an electrical generator.

According to one preferred embodiment of this invention, a man-madeisland with solar collection facilities includes a floating platform,the platform primarily comprising a flexible cover, or foil, whichextends across an outer ring structure and is sealed thereto. The topcover is an industrial-grade, long-life and UV-resistant material thatis either vulcanized and or clamped or attached by any other suitablemanner to the outer ring structure, so that it is airtight. This createsan enclosed volume below the cover. A compressor system is installed soas to be in fluid communication with the enclosed volume and operable tocreate a slight over-pressure under the cover. Current studies show thatan over-pressurization of about 0.005 bar should be sufficient, but insome situations it could be substantially greater. Also, theover-pressure is dynamically adjustable, as described below, to achieveand maintain a desired floating effect and to position the height of thecover, or membrane. It may be desirable to pressurize the enclosedvolume to the point of creating an upwardly directed bulging effect, tofacilitate rainwater runoff in a radial outward direction. Also, thecover could include channels to facilitate runoff in the desireddirection. In fact, the runoff could be used as part of a sea-waterdesalinization system. To achieve the desired over-pressurization, aplurality of compressors, i.e. pumps, may be used.

For the land-based system, a land wire facility operatively connects theman-made island to the local grid. Where no substantial electrical gridis available for correction, a hydrogen production facility isconnected. For the water-deployed version, the man-made island has asufficient number of propulsion devices driven by electrical or otherpower distributed along the outer ring structure. These propulsiondevices may move the island to a desired location, and also turn theisland to a desired orientation relative to the sun.

The land-based version of the man-made island of this invention hascentering mechanisms, namely wheels, for centering the island on itsaxis of rotation within the trough. To turn the island, this structureuses driveable wheels that roll on the outside of the concrete ring.Because the man-made island is floatably supported, the power actuallyneeded to rotate the island is minimal. Relatively small motorsdistributed around the outer structure will be suitable for turning theisland by approximately 180 degrees in one day due to the symmetricallayout of the collectors, although it would also be possible to turn theisland 360 degrees in one day.

To reduce the total weight of the island, and to reduce susceptibilityto flexing due to wind, the solar radiation collector modules supportedon the platform have a flow-through lightweight design which allows airto actually flow through the concentrator panels. Such collectors can beassembled from plain industrially manufactured, mirrored band steel oraluminum. This type of design substantially reduces costs and weightcompared to typical parabolic trough designs. Also, this design can beeasily assembled in countries close to the equator, where difficultmanufacturing processes, e.g., the bending of large-scale aluminummirror elements, may not be feasible.

The enclosed volume of this man-made island is bounded by the outer ringstructure, the cover, and the water surface (for the sea-based version),or the land surface (for the land-based version). For the land version,the sealing effect for the enclosed volume is achieved in part by theconcrete trough. One particular advantage with the land version is thatthe earth surface underneath the cover can remain untreated. Also, thissurface could hold some of the technical installations used to operatethe island. Thus, those installations would not necessarily have to besupported by the outer ring structure, as would be the case for theman-made island floating at sea. If an installation were actuallylocated under the platform, for the land version, overlying sections ofthe cover could be made of transparent material. This would provide forsome ambient sunlight to reach facilities below, in which the operatingteam is working.

An upper structure resides above the cover, and supports the solarradiation collector modules. According to a first preferred embodiment,this upper structure is a space frame. According to a second preferredembodiment, a pre-tensioned cable system spans the cover, and the outerring structure holds the mounts for these cables. Still further, ahoneycomb structure could be used as this upper structure. The aircushion under the cover is maintained at a pressure that actuallysupports the upper structure. For this purpose the upper structure, oreven the modules or the cover, holds a plurality of sensors, such asstrain gauges, that are interconnected in a network that is operativelyconnected to a computer, which is in turn connected to the compressorsystem. The sensors measure a desired measurable condition related tothe cover, such as the strain on the upper structure, at differenceplaces around the cover. The computer uses an appropriate algorithm andcorresponding software to control the compressor system to dynamicallyadjust the air pressure under the cover, to minimize the strain on theupper structure, or to address the sensed condition in an appropriatemanner. It is to be understood that any one of a number of other forcemeasuring devices could be used to dynamically sense and analyze themechanical load on the cover, the upper structure, or the modules, andto initiate an appropriate change in over-pressurization.

This man-made island is particularly lightweight because the upperstructure holding the solar concentrator modules will barely have to beable to support its own weight. Any excess forces induced by wind or anyother atmospheric or untoward effects can be compensated by theoverpressure cushion under the flexible cover, particularly viaappropriate sensors and dynamic control of the compressor system.

According to another aspect of the invention, the outer ring structurehas additional support frames on the outside thereof, to holdphotovoltaic (PC) elements. Electrical power generated by those PVelements and their battery storage and DC/AC converter facilities couldbe used to power the positioning systems of the island and also theoperating room systems, such as the drive system, and the compressorsystem.

According to still another aspect of the invention, the sea-basedversion contains propulsion equipment mounted at multiple points aroundthe outer ring structure, to move the island north and south across theequator in parallel with the seasons. This enables the island tomaintain a vertical position under the sun's daily path. It has beenshown that solar power output could be increased by up to 15 percent peryear if a solar energy production facility is actually able to followthe sun's path in the manner suggested here. The positioning system ofsuch an island could include a GPS system with appropriate computingequipment including the algorithms and associated software establishinglatitude and longitude based on the law of Cook (seehttp://fred.elie.free.fr/cadrans_solaires.htm. The same positioningsystem would also maintain the island's angular position during the daywhen it essentially turns through about 180 degrees to follow the sunfrom rise in the east to sunset in the west.

A brief calculation of the potential output of this man-made island,with a diameter of 500 meters, is shown below. Such an island would havea surface area inside the outer ring structure of about 195,000 squaremeters. Solar radiation in the tropics is approximately 1 kW per squaremeter. Assuming a somewhat conservative overall transformationefficiency (concentrators, Rankine cycle etc.) of between 10 and 20percent, the peak output of such an Island can be estimated to be over30 MW. This assumes that the island operates at peak power during about8 hours per day. For purposes of this calculation, additional powergenerated at less than peak output during the morning and evening hourshas been omitted. This would result in an output of approximately 240MWh per day or about 85000 MWh per year, assuming that 15 days per yearare reserved for maintenance operations. Thus, one such island couldproduce an amount of electrical power in one year that is approximatelyworth $12.75 million at an average sales price of $0.15/kWh. Accordingto a more conservative assessment, the mean power over a period of 24hours would be 7.4 Mw. Using the same general assumptions as statedabove, this would result in an output of approximately 177 MWh per day,or about 61,850 MWh per year, worth approximately $9.28 million at thesame average sales price listed above.

The economics behind this man-made island become more attractive as thesize of the island increases. Also, the increase in size furtherincreases stability for the water-deployed version, particularly inadverse weather. Thus, this inventive man-made solar island represents amajor contribution toward sustainable energy production that will sodesperately be needed in the near future.

The over-pressurization of the enclosed volume below the cover plays asignificant role in supporting the solar radiation collector modules.More particularly, to generate electricity from solar radiation at aneconomically viable cost, the surface area needed is extremely large.Although commercially available solar collectors continue to improve inefficiency, the surface area requirements, i.e. the surface areaoccupied by the collectors, are still immense. The need for largesurface area creates other practical considerations, namely how tosufficiently support the collectors on a load bearing structure that isalso reorientatable relative to the position of the sun. With thisinvention, the answer is threefold. First, the large outer ringfloatably supports the periphery of the island. Second, theover-pressurized volume below the cover helps to balance the load on theplatform. Third, the use of an appropriate upper support structure, i.e.a lightweight space frame, or alternatively, a tensioned cable system,or a honeycomb structure, further assures adequate lateral mechanicalsupport for the solar collector modules mounted on top.

A water supply pipe (inbound) and a steam pipe (outbound) connect to thesolar radiation collector modules via a rotary joint located at thecenter of the island. This joint must be able to accommodate therotation of the island. This can be done by a coaxial configuration, acoaxial swiveling joint or even by a suitable length of a flexible hose.

Once these pipes have reached the top of the platform, they are routedalong the rows of the solar radiation collector modules, to generateusable steam via heat pipes onto which the sunlight is concentrated.Because the length of the various pipes extending from the center of theisland to all of the various collector modules will differ, pressureregulator valves are used to moderate and control any undesired pressuredifferences.

Along the modules, various layouts or arrangements of the heat pipelayout are possible. One such arrangement involves running the outboundwater lines along the tops of the heat pipes of the solar collectormodules, to preheat the water flowing in these upper pipes as a resultof their proximity to the respective heat pipes located therebelow.

The present invention also contemplates the capability of cleaning andservicing the solar collector modules via a driveable cart, or otherdevice, that moves along a rail or track that extends alongside the rowsof collectors. This device could be a robot that directs pressurizedfluid, most likely air, at the surfaces of the modules. The track couldbe a dual rail track which supports a wheeled cart, or even amonorail-type track. The wheeled cat configuration enables travel alongthe rails to any desired position on the platform to provide access forany needed maintenance.

These and other features of the invention will be more readilyunderstood in view of the following detailed description and thedrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the man-made island constructedaccording to a first preferred embodiment of the invention.

FIG. 1A is a horizontal sectional view which schematically shows asea-bound version of the man-made island, according to one aspect of theinvention.

FIG. 2 is a horizontal sectional view which schematically shows aland-based version of the man-made island, according to another aspectof the invention.

FIG. 3 is a plan view, in schematic form, which shows a land-basedversion of the man-made island of this invention.

FIG. 4A is a horizontal sectional view which schematically shows theouter ring structure and the trough of a land-based man-made islandaccording to one preferred embodiment of the invention.

FIG. 4B is a horizontal section view, similar to FIG. 4A, whichschematically shows yet another variation of the outer ring structureand the trough, for the land-based version of the man-made island ofthis invention.

FIG. 5 is a perspective view of a drive wheel unit, shown connected tothe outer ring structure, according to one preferred embodiment of thedrive mechanism of this invention.

FIG. 6 is a perspective view, star to FIG. 4, of a centering wheel unit,shown connected to the outer ring structure, according to one preferredembodiment of the centering mechanism of this invention.

FIG. 7A is a perspective view of a pod supporting a portion of alightweight space frame on the cover of the platform, in accordance witha first preferred embodiment of the upper structure of this invention.

FIG. 7B is a horizontal view which schematically shows the pod and otherstructures shown in FIG. 7A.

FIG. 8 is a perspective view which schematically shows the bottom of apod of the type shown in FIGS. 7A and 7B.

FIG. 9 is a perspective view which schematically shows a computer-modelgenerated simulation of the depressions that could occur on the cover ofthe man-made island of this invention.

FIG. 10 is a horizontal view that schematically shows a second preferredembodiment for the upper structure of this invention, namely a cablesystem that cooperates with a plurality of pontoons, which in turn holdsupport boards onto which Fresnel-type solar concentrators are mounted.

FIG. 10A is a perspective view showing an alternative pontoon structure.

FIG. 11 is a horizontal view which schematically shows a third preferredembodiment for the upper structure of this invention, a honeycombstructure onto which a Fresnel-type collector is mounted.

FIGS. 12A and 12B are perspective views which show two alternativestructures for routing fluid, i.e. water and/or steam, to and from theisland 10 via a rotary joint located at the hub 11.

FIG. 13A is a longitudinal view along one of the rows of Fresnelcollectors, showing a rail supported cart which facilitates service andmaintenance.

FIG. 13B is a cross-sectional view along lines 13B-13B of FIG. 13A.

FIG. 14 is a perspective view which shows another aspect of the cartshown in FIG. 13A.

DETAILED DESCRIPTION OF THE DRAWINGS

The present application claims the priority benefit of U.S. ProvisionalApplication Ser. No. 60/892,956 filed Mar. 5, 2007, entitled “SolarIsland”; and PCT Application No. US2008/55925, filed Mar. 5, 2008, withthe same title. These applications are expressly incorporated byreference herein, in their entireties.

FIG. 1 shows a man-made island 10 constructed in accordance with onepreferred embodiment of the invention. The island 10 generally comprisesa horizontal platform 12, which in turn includes an outer support ringstructure 14 that is spanned by a flexible cover 16. The cover 16 may beof any suitable flexible material that can be sealed along its opposinglongitudinal edges, such as for instance by gluing, heat welding, orvulcanizing the adjacently located edges. In an initial prototype of theinvention, for the cover 16 applicants are using a industrial foil knownas SIKA Sarnafil TS 77-20. The island 10 includes a central hub 18 whichwill be described later in more detail.

The platform 12 supports a plurality of solar radiation collectormodules arranged end to end in a plurality of parallel rows 19. Anygiven row 19 of modules includes a plurality of wire supported uprights20, which in turn hold a horizontally oriented heat pipe 21. Each of therows 19 includes a plurality of lower, parallel mounted solarconcentrators, or reflector panels 22. Each of the concentrators 22 isfixed at a desired angle, so that all of the reflectors 22 reflect, ordirect, sunlight upwardly toward the heat pipe 21. The platform 12rotates to keep the rows 19 oriented towards the sun.

A water supply pipe and a steam pipe are routed to the central hub 18,and connect to two conduits 24 that extend in opposite directions. Theconduits 24 connect to sub branches 24 a that extend generally along thecenter of the island 10, so that in each row 19, the supply water canflow out and back along the respective heat pipe 21.

FIG. 1 also shows a plurality of pods 25 distributed across the uppersurface of the cover 16, in a grid pattern designated generally byreference number 26. Although not shown in particular detail in FIG. 1,the pods 25 support a lightweight space frame 27, which generallyoccupies the spaces designated by the gridlines 26 in FIG. 1. The spaceframe 27 in turn supports the rows 19 of solar radiation collectormodules. The space frame 27 is one form of the upper structure used tosupport the rows 19 of modules.

FIG. 1A shows a sea borne version 10 a of the island, bounded by asea-borne outer ring 14 a. Propulsion equipment 14 b, i.e., suitablymounted outboard motors, are located at a selected number of points onthe periphery of the sea borne ring 14 a.

As described above, land-based or sea-based, this inventor contemplatesa man-made island as a floating structure. FIG. 2 shows more details ofthe structural components of one preferred embodiment of the land-borneversion of this man-made island 10. More particularly, FIG. 2 shows theoverall structure, and the manner in which the island 10 is floatablysupported by the outer ring 14. Preferably, the ring 14 is made ofconnectable, prefabricated segments of steel, concrete, plastic,aluminum, or any other suitable material. If the segments of the ring 14are made of steel, they are preferably welded together. Particularly fora sea-based version of the island 10, the segments have internal supportstructures. These internal support structures isolate adjacently locatedsegments of the ring 14, so as to isolate any leaks that might occur. Inone prototype construction of the land-based version of this island 10,the platform 12 is about 85 meters in diameter, the segments have adiameter of about two meters, and a length of about 7.5 meters.Preferably, the sections of the ring 14 are placed aid inter connectedwhile in the trench 28, and preferably supported on a temporarystructure which can then be removed after the trench 28 is filled withwater 29. The trench 28 must be able to support the weight of the ring14. For the prototype, applicants estimate that the ring 14 will have atotal weight of about 100 tons (100,000 kg), which corresponds to aweight of about 380 kg per square meter.

FIG. 2 shows the outer ring 14 floatably located within a trench ortrough 28. As shown in FIG. 2, the trench has an inside wall 28 a, abottom wall 28 b, and an outer wall 28 c. The trench 28 is preferablymade of concrete. The thickness of each of the walls 28 a, 28 b, and 28c is determined according to local geological surveys and any applicablebuilding code. The trench 28 includes a fluid of suitable viscosity, andparticularly a liquid such as water 29, so as to float the support ring14.

FIG. 2 also shows the enclosed volume 30 located below the cover 16, andfurther defined, or bounded by the ring 14, the water 29 in the trough28, and the ground 31 or floor surface located in the center of theisland 10. Preferably, the surface 31 is even with the top of the insidewall 28 a. This may be done by sand-filling, and the sand then coveredby PVC foil of 2 mm thickness, preferably a flexible polyolefin basedfoil reinforced with polyester thread and/or a fleece made ofglassfibre. A compressor system 32, preferably a plurality ofcompressors, or pumps, is located so as to be in fluid communicationwith the enclosed volume 30. In FIG. 2, the pump 32 is shown below thefloor 31 in the middle of the island 10. Nonetheless, it could also becentrally located within an operations room or facility for operatingthe island 10, or even placed on the ring 14. The pump 32 pumps air intothe enclosed volume 30, as shown by directional shows 34, to maintain asuitable over-pressurization condition beneath the cover 16 and withinvolume 30. Applicants currently expect that the actual amount ofover-pressure within the enclosed volume 30 will be about 0.005 bar,although that value may vary somewhat depending upon the dynamicconditions, and in some situations it could be substantially greater.FIG. 2 also shows an upwardly extending outer rim structure 14 a, whichextends upwardly from each of the segments of the ring 14 to create anouter top surface 14 b around the top of the ring 14.

FIG. 3 shows one example of the land-based version of this man-madeisland 10, including a radially oriented subsurface tunnel 35 thatextends outwardly from the center hub 18 of the structure, beyond theouter wall 28 c of the trench 28 to an energy facility 36, which may bea turbine generator or other facility for storing or using the solargenerated steam produced by the island 10. Preferably, the tunnel 35carries the water pipes which connect to the conduits 24, and also anyelectrical connectors. The tunnel 35 floor slopes downward from thecenter of the island 10, so as to extend below the bottom of the trench28 and also to prevent any water or other liquid from flowing to thecenter of the island 10. A pond 37 is located nearby to supply water tothe trench 28, as needed. It preferably connects to trench 28 frombelow, to facilitate quick draining of the trench 28.

FIG. 3 also shows another view of the rows 19 of modules. Generally, foreach module the concentrators 22 are about 8 meters in length.

FIG. 2 and also FIG. 4A show details of a centering mechanism 38 thatcenters the island 10 on its central axis. More specifically, thecentering mechanism 38 resides radially beyond the ring 14 and withinthe inside surface of the outer wall 28 c of trench 28. This centeringmechanism 38 comprises a bracket 39 mounted to the ring 14, whichsupports a rotatable wheel 40 that resides in contact with the outerwall 28 c. It is important that the inner surface of the outer wall 28 cbe constructed so as to be perfectly round, or with a very lowtolerance. This requirement is necessary because angular adjustment ofthe island 10 is achieved via these wheels 40. The invention alsocontemplates an alternative mounting option, that of mounting thebrackets 39 on the outer wall 28 c so that the wheels 40 contact thering 14.

Although the number of wheels 40 may vary, applicants expect that twelvesuch wheels 40 will be needed around the circumference of the ring 14,with the wheels spaced every 30 degrees. Nonetheless, additional wheelscould be used to more equally distribute the load between the outer wall28 c and the ring 14. The wheels 40 can be standard automotive wheels.Also, some of the wheels 40, preferably four, serve the additionalpurpose of rotatable driving the ring 14 about its axis to a desiredposition, to optimize the performance of the reflectors 22. Thus, someof the wheels 40 are part of the centering mechanism and the drivingmechanism. FIG. 4A also shows a motor housing 50, which indicates thatthe wheel 40 shown is one of the four dual purpose wheels 40.

Those skilled in the art will appreciate that at any given time theforce between the wheels 40 and the wall 28 c will act on only one sideof the ring 14, depending upon the direction of the wind. Thus, onlyabout half of the centering wheels 40 will be used to transmit angularforce to the ring relative to the outer wall 28 c. Nonetheless, theouter wall 28 c and its foundation must be dimensioned and reinforced soas to carry this load. If there is no wind at all, or very low wind,then all of the wheels 40 will contact the outer wall 28 c and carry therotational load, although the load will be more evenly distributed aboutthe entire circumference of the ring 14.

FIGS. 4A and 4B show the outer ring structure 14, along with some of thestructural details of the island 10. Due to the larger size of FIG. 4A(compared to FIG. 2), FIG. 4A shows more clearly all outer bracket 42,preferably a steel ring torus with a U-shape, turned on its side, whichsecures or clamps the outer peripheral edge of the cover 16. FIG. 4Aalso shows some aspects of one preferred structure used to support therows 19 of solar collector modules. More particularly, FIG. 4A showsdetails of a tensioned cable system which coacts with the pod 25. It isexpected that the cable 46 will need to accommodate a tension force inthe range of about 10-25 KN. More particularly, a fed mounting support44 holds the outer end of a tightened cable 46 which spans across theisland 10 above the cover 16, in a manner which enables the pods 25 toessentially hang from, or be suspended between, the cable 46 above madthe cover 16 below. Preferably, the pods 25 are adapted to accommodatethe cable 46 of such a cable system and also the space flame components,to enhance versatility in constructing the island 10 and in supportingthe solar collector modules.

FIG. 4B is similar to FIG. 4A, except FIG. 4B shows another variation ofthe invention wherein the ring 214 stores steam 114 generated by thecollector modules, and the ring 214 is encased within a square-shaped(in cross section) outer insulation section 215. FIG. 4B also shows anoutwardly extending skirt 228 d that extends from the ring 214 to theouter wall 228 c of the trench 228. This skirt 228 d is usable with theother variations of the invention. The skirt 228 d helps to preventevaporation of fluid from the trough 228, and may also aid in preventingdust or other debris from falling therein.

FIG. 5 more clearly shows one of the centering wheels 40 that is alsoused to rotatably drive the island 10. This is achieved by mounting adrive mechanism, i.e. a motor 50 a, to the same structure which supportsa centering wheel, as shown in FIG. 6.

In either case, the wheel 40 has a bracket 39 mounted to the ring 14.The bracket 39 includes a horizontally oriented hinge axis 39 a, and aspring 41 that acts as a shock absorber between the hingedly connectedsections of the bracket 39 (hingedly connected with respect to the axis39 a). FIG. 4A shows a motor housing 50, which covers the motor 50 athat is shown in FIG. 5. Preferably, the drive mechanism includes aspeed reducer 52 and an adapter 53 mounted to the bracket 39 with thewheel 40. Still further, as shown in FIG. 3, the motor housing 50operatively connects to a computer controller 70 via an electricalconnection, to rotatably control the angular position of the island 10.This electrical connection could be wireless, if desired, or via anyother suitably convenient electrical connector.

FIG. 7A shows an enlarged view of one portion of this man-made island10, and particularly a portion where a space frame 27 mounts to one ofthe pods 25. FIG. 7A particularly shows that the space frame 27preferably uses an I-beam construction. FIG. 7A also shows that a top 25a of the pod 25 includes upwardly directed channel brackets 25 b forsecurely holding the lower ends of the space frame 27. These brackets 25b may be part of a top piece 25 a of the pod 25, in the form of a plate,to which the brackets 25 b are connected by any sufficient securementmechanism. FIG. 7A also shows the concentrators 22 supported on alattice or pallet-like structure 23, which also preferably uses anI-beam construction.

In addition to the space frame 27, or as an alternative thereto, thecable system can be used for supporting the solar collector modules.FIGS. 7A and 7B show the cable 46 in phantom, to illustrate that it isan additional, or an alternative structure for providing support. Also,as shown in FIG. 7B, the pod 25 includes upwardly extending hangers 25 cwhich connect to the cable 46. Still further, FIG. 7B shows a sensor 60,which may be a strain gauge, mounted in position to sense the strain onthe space frame 27. As mentioned previously, a plurality of such sensors60 are distributed throughout the platform 12, and are operativelyconnected in a network (not shown) to convey to the computer controller70 (FIG. 3) the sensed conditions. The sensors 60 may be adapted tosense any one of a number of different measurable conditions.Preferably, the controller 70 also causes the compressor system 32 torespond appropriately to the sensed conditions, by dynamically adjustingthe amount of over pressurization.

FIG. 8 shows a bottom profiled surface 25 d of pod 25. FIG. 9 is acomputer simulated view of the cover 16, with three noticeable dimples,or depressions, as a result of the load supported thereabove. Thesedimples are designated via reference numerals 16 a, 16 b, and 16 c. Theyshow the need for dynamic over-pressurization and strain sensing toachieve a horizontal position of the solar collector modules mountedthereabove. For this embodiment of the invention, or any embodimentinvolving spaced pods located on the cover, it would be preferable toinclude drainage valves within the cover, to avoid rainwateraccumulation around the pods. Such valves need to remove water from thetop of the cover, while preventing any pressure leakage from under thecover.

FIG. 10 is similar to FIGS. 4A and 4B, but shows more details of thecable and pontoon structure used to support the rows 19 of solarcollector modules. In this particular embodiment of the invention, thecable 46 spans across the top of the cover 16, transversely across aplurality of pontoons 72 which are arranged in parallel rows on thecover 16. The pontoons 72 can be made of plastic or any other suitablelight weight material. Applicants contemplate using pontoons of the typeindustrially manufactured and distributed by e.g. RobinKunstoffprodukte, of Teterow, Germany and Tecutus K G (GmbH and Co.),also of Teterow, Germany. Preferably, the cable 46 engages a pluralityof braces, or boards 74, supported on top of the pontoons 72 (or rows ofpontoons). The boards 74 support the lattice 23 which holds the solarconcentrators 22. FIG. 10 shows depressions formed in cover 16 alongsidethe pontoons 72. These parallel depressions facilitate the runoff ofrainwater, and also eliminate a centrally located bulge that couldresult from the over-pressurization. Surface runoff may be morecontrollable because it will generally flow to these known depressions.

FIG. 10A shows another version of the pontoon, designated by referencenumeral 72 a. This pontoon 72 a has a formed, preferably molded, topsurface structure designed to facilitate holding of the upper structureand/or other structure which supports the modules.

FIG. 11 shows a side view of yet another embodiment of the upperstructure used to support the solar radiation collectors. Moreparticularly, FIG. 11 shows a honeycomb-type structure 75 residingbetween the cover 16 and the solar collectors 22 c and also supported bycable 46.

FIGS. 12A and 12B show variations on the rotary joint for use at thecenter hub 18 of the island 10. More particularly, FIG. 12A shows aninlet pipe and an outlet pipe, designated 80 a and 80 b respectively,both of which include a respective sleeve 81 a and 81 b, which permitssome relative rotation between the upper and lower sections thereof; atleast in the range of about 240 to 260 degrees. FIG. 12B shows a coaxialversion 82 of the rotary joint. More particularly, water inlet 84supplies water to an outer annularly shaped flow passage within outerpipe 85, for water flowing toward the solar collector modules. After thewater has been heated and steam has been created, it returns via centralheat pipe 86 (which is rotatable with respect to outer pipe 85 and tothe inlet 84). The steam generated via the solar collectors eventuallyflows toward the bottom of the rotary joint 82 and exits the joint via asteam outlet 88. Those skilled in the art will appreciate that one ormore pumps (not shown) may be used to cause the water, i.e., the waterto be heated, to flow to the island and to the solar collector modules.Similarly, those skilled in the art will also appreciate that one ormore pumps (also not shown) may be useful for assisting the outboundflow of steam from the island. To some extent, the bleed for theseadditional components will depend on the location and the type of energygenerating device that is operatively connected to the output line fromthe island.

FIGS. 13A and 13B show two additional features of the invention. Moreparticularly, FIG. 13A shows a wheel supported cart 90 which rolls alonga pair of spaced rails 92 arranged parallel with the rows 19 of thesolar collector modules. This facilitates maintenance of the collectors,and does so in a manner that does not interfere with the solarcollection structure.

FIG. 13B shows one embodiment for incorporating a preheating featureinto this invention. More particularly, FIG. 13B shows the uprights 20of cone of the rows 19 of solar collector modules, and the heat pipe 21configured as a coaxial pipe structure 94 that spans between theuprights 20. More particularly, the pipe structure 94 is a coaxial pipewith an outer annular channel 94 a and a centrally located inner channel94 b. With the panels 22 of the solar collector modules concentratingand directing the sunlight upwardly, water flowing outbound (to the leftin FIG. 13B) via central channel 94 b is preheated by the heat emanatingfrom steam flowing in the outer channel 94 a (which is flowing to theright in FIG. 13B). The outer channel 94 a receives the greatestconcentration of redirected radiation from the sunlight. Thus, theheated steam within channel 94 a also causes heat to emanate radiallyinwardly to preheat the fluid flowing in the inner channel 94 b. Thissame principle could be used with an upper outbound channel 94 a and alower return (steam generating) channel 94 b, if the coaxial version ofthis piping structure proves too cumbersome or too expensive tomanufacture or install.

FIG. 14 shows the capability for the cart 90 to move laterally along, ortransversely to one of the rows 19 of solar collectors, at the end ofthe row 19, as shown by directional arrow 97, along a transverselydirected track. This enables the cart 90 to service the entire surfacearea of the cover 16 occupied by the rows 19 solar collector modules. Asshown in FIG. 3A, adjacent row 19 access could also be obtained byadding an outer half circular track 94 a to connect adjacently locatedrows. These connector tanks can be removable, for temporary use, toaccommodate multiple rows 19. The type of structure can be used forregular servicing of the island 10, for example, for cleaning the panels22 of the solar collector modules.

One embodiment of the invention contemplates that the outer ringstructure, in the case of the water-deployed man-made island 10 a (shownin FIG. 1A), would contain a hydrogen production facility in ahermetically sealed pipe section attached under the outer ring structure14 a. Such a hydrogen production facility could be completely submerged,and run in a way that the electrolysis generator could operate in anevacuated or an inert gas environment, thereby to substantially reduceany potential accident risks. It is also envisaged to use two concentricpipe sections in the construction of such a hydrogen productionfacility—in other words the electrolysis generator would then be housedin a double-walled structure.

Hydrogen production and distribution facilities are generally notconsidered to be dangerous; they are not systematically prone to risksof uncontrolled combustion. However, ashttp://www.eihp.org/public/Reports/Final_Report/Sub-Task_Reports/ST5.2/RISK%20ASSESSMENTS%20OF%20H2-REFULLOMG%20STATION_Onsite_%20CONCEPTS.pdfshows, these facilities require frequent maintenance and ongoingsurveillance in order to effectively control such risks. An evacuatedenvironment or an environment filled with inert gas would substantiallyreduce those risks, as hydrogen and oxygen gas sensors would immediatelywarn about the risk of a leak developing. For regular maintenance everyfew months, such a hydrogen production facility could be shut off andoutside air pumped in before the maintenance crews enter the scene.

For the land-based version of the man-made island, a hydrogen generationfacility would be constructed at a sufficient distance from the solarisland 10 to prevent any potential hazardous exposure.

While this specification describes a number of preferred embodiments andother variations of the invention, those skilled in the art willappreciate that the particular structures shown and described aresusceptible to a reasonable degree of modification, and hence, theinvention is not limited in scope to the specific details shown anddescribed. Application wishes only to be limited by the broadestreasonable interpretation of the following claims.

1. A solar energy collection system comprising: a platform floatingabove a body of fluid, the platform including an outer ring structureand a flexible cover that sealingly encloses a top end of the outer ringstructure, thereby to define an enclosed volume below the cover; acompressor for creating a suitable over-pressure condition within theenclosed volume; a plurality of solar radiation collector modules heldabove the cover; all upper structure located above the cover and holdingthe solar radiation collector modules; and the platform being rotatableabout a center horizontal axis thereof, thereby to enable theorientation of the solar radiation collector modules to be variable andplaced at a desired orientation depending on the angular position of thesun.
 2. The solar energy collection system of claim 1 wherein the systemis land-based and further comprising: a lower ring-shaped troughresiding below the outer ring structure and adapted to hold a fluid ofsuitable viscosity, thereby to floatably support the outer ringstructure on the fluid within the trough.
 3. The solar energy collectionsystem of claim 2 wherein the fluid is water.
 4. The solar energycollection system of claim 1 wherein the suitable overpressure is atleast 1/10 bar.
 5. The solar energy collection system of claim 1 whereinthe outer ring structure is at least several meters tail.
 6. The solarenergy collection system of any of the prior claims wherein the coverhas at least one of the following characteristics: a) UV resistant; andb) of foil composition.
 7. The solar energy collection system of claim 1and further comprising: a drive mechanism adapted to driveably rotatethe platform about its center axis to a desired position, depending onthe position of the sun; and a computer operatively connected to thedrive mechanism and adapted to control the position thereof according toa suitable algorithm.
 8. The solar energy collection system of claim 1and further comprising, a plurality of strain gauges mounted on theupper structure and operatively interconnected in a network, the straingauges adapted to sense the strain on the upper structure; mid acontroller operatively connected to the network and also to thecompressor, and adapted to dynamically adjust the over-pressurecondition within the enclosed volume so as to minimize the mechanicalload on the upper structure.
 9. The solar energy collection system ofclaim 1 and further comprising: an energy conversion system operativelyconnected to the solar radiation collector modules.
 10. The solar energycollection system of claim 9 wherein the energy conversion systemcomprises an electrolysis generator for producing hydrogen.
 11. Thesolar energy collection system of claim 10 wherein the electrolysisgenerator is located within the outer ring structure.
 12. The solarenergy collection system of claim 1 wherein the platform is sea-based,and further comprises: a plurality of propulsion mechanisms located atselected positions around the periphery of the outer ring structure, andoperable to move the platform to a desired location to optimize theoperation of the solar radiation collector modules.
 13. The solar energycollection system of claim 1 and further comprising: rainwater drainagechannels formed in the cover to facilitate rainwater runoff; and a watercollection device operatively connected to the rainwater drainagechannels.
 14. The solar energy collection system of claim 13 and furthercomprising: a sea-water desalinization facility in cooperation with thewater collection device.
 15. A method for collection solar energycomprising: floatably supporting a platform, the platform beingrotatable relative to a center axis, the platform including an outerring structure and a flexible cover extending across and sealinglyenclosing an upper end of the outer ring structure, thereby to define anenclosed volume below the cover, the platform holding an upper structurethat supports thereon a plurality of solar radiation collector modules;and pressurizing the enclosed volume to a sufficient degree ofover-pressurization to maintain a desired floating effect for theflexible cover and the solar radiation collector modules locatedthereon.
 16. The method of claim 15 wherein the outer ring structure ofthe platform floatably supports on a fluid.
 17. The method of claim 15and further comprising: sensing a strain condition associated with theupper structure; and dynamically adjusting the over-pressurization ofthe enclosed volume in response to the sensed strain condition.
 18. Themethod of any of claim 15 and further comprising: driveably rotating theplatform about its center axis to maintain the solar radiation collectorin a desired, optimum orientation relative to the position of the sun.19. The solar energy collection system of claim 15 wherein the platformis sea-based, and further comprising: propelling the platform viacontrolled operation so as to steer the platform north and south acrossthe equator, as desired, and to maintain the platform in a position thatis oriented vertical to the sun.